Reference Current Computation Method Based on Adaptive Low-Pass Filter for Active Power Filter

The performance of reference current computation method based on Fryze, Buchholz, Dpenbrock (FBD) algorithm is focused on. An adaptive low-pass filter (LPF) based on fuzzy logic is proposed, which is composed of two two-order Butterworth LPFs, and fuzzy logic is developed taking changing amplitude of load current and harmonic number of the lowest harmonic current into account. The selection and switching time of two LPFs is determined by result of fuzzy logic and rising time of two-order Butterworth LPF with cut-off frequency at 10 Hz. Compared with traditional reference current computation methods, FBD algorithm based reference current computation method with adaptive LPF is of high accuracy and better dynamic performance even under unbalanced voltage circumstance. MATLAB simulation results and experimental results prove the validity and effectiveness of the proposed reference current computation method.